The River Tyburn, another lost river of London. The Tyburn originally arose from two smaller tributaries in the hills of Hampstead, flowing down through Marylebone, Mayfair and Picadilly. From here things get slightly regal as it flows underneath Buckingham Palace and onwards towards its confluence with the Thames. Now known as the King's Scholars' Pond Sewer, it is completely buried and incorporated into the london sewer network. As another monster river of old, exploration of the Tyburn has taken several trips over the recent years, with us finally seeing the entire explorable length at the start of 2009.

Our Tyburn journey starts near regents park, at a small chamber which sends the upstream contents roaring down into the MLS No.2. Anything further north became too small considering the amount of content flowing through it, so we aimed for everything south!. An 8ft, red and concrete pipe lay before us. So with maps at our hips, cameras in our bags, and Tyburn on the mind we ventured forth.

The upstream ends of the Tyburn are in dire need of attention. Many of the branches with other sewers are damaged and falling to pieces. Careful markers have been placed over the cracks to see how much they grow overtime, small attempts with concrete at some quick cosmetics the dish of the day. The pipe shifted into a smaller egg shape, before long reaching the Regents Canal. The pipe split into two rather unfavourable 4ft pipes, carrying the flow over the canal via a bridge, fun, but the show must go on. Slowly striding through the black, chunky liquid, dangerously close to catching some splash in the face, bags catching at every possible opportunity, thank god it was only 40 meters.

Reunited with the 7ft egg we continued south, passing our first piece of drain graffiti ever. A small mark from one of London's legendary force of sewer workers, the flushers. Or more precisely, The Happy Flusher!, age unknown. I couldn't help but feel respect for these men, with ranks of less then forty it is their sole job to keep London's bowels running. While we pass off 4ft pipes as a quick bit of inhospitality, they spend years in them removing the fat, concrete and oils from the careless folk above. My hat comes off to you gentlemen.

As we drew close to Marylebone the pipe shifted once more into a 8ft arch. We found ourselves directly adjacent to the Baker Street station. The tunnel was loosing a war against the rumble and vibrations of passing trains beneath. Large sections of the brickwork had broken away, leaving huge scars along the walls and ceilings. Id hate to think of what disaster would ensue should this section fall away, but its probably more secure then it looks, i hope.

We progressed further south, every new side pipe adding a considerable amount of flow to the mix, a loud roar audible in the distance. As we continued the noise grew louder and louder. We were now wading in knee, deep fast flowing fudge that looked green in colour. This was the first time since Serpents Lair i had to rethink my decisions for being here, no really, why?!. We trudged around the bend, the mist increased considerably, the cause, a small staircase. Now in a way if this was in any other drain it wouldn't really get another look. But due to the speed and amount of sewage flowing in the Tyburn it became an impassable pit of death. A scary watermark on the adjacent ceiling showing just how scary things could get. For now our navigation would have to wait, as there was no way to traverse this beast.

So another day, another trip, this time starting from where we left off, the staircase of death. Now at a sizeable 9ft the Tyburn diverts into the MLS No.1, and so walkablilty returned. Although the tunnel was dry, like every other sewer after a interception, there was turd everywhere. We passed yet more small sewers which eventually brought in enough flow to clear the floor, another interceptor of unknown destination and finally, a large red brick oval chamber.

The chamber served as a overflow into the "Egg" relief sewer, which flows east and under the Westbourne, then south towards the Thames. Two more side sewers connect into this chamber increasing the flow, making it just a bit more, fun. Once more the floor became excruciatingly slippery as we began south. Thankfully a few hundred meters down, the Tyburn dumps its content into the LLS No.2, clearing the way for a dryer pipe. We marched on.

We were now directly underneath Buckingham Palace, but sadly you wouldn't know it. There was no plaque of recognition, no golden poop chutes laden with velvet lining, nothing. Quite frankly, if i had been told i would have happily walked on by. Oh well its a interesting fact to tell your mates at the pub i guess. Not many can say they've stood in the Queens regal faeces can they.

Several twists and turns later we approached a large hydraulic flap, used to stop the flow completely if problems were encountered further downstream. This brought with it a dilemma, do we go past it?. Pros of going through were that its more unseen tunnel to explore but the cons included, getting trapped, squashed and in the worst case drowning. We really didn't know what might happen should it close behind us. Eventually we came to the conclusion that as this was built long after the Tyburn's original burial, there should be no reason why manhole exits would stop at this point, so we pushed on.

Turns out there's not a great deal in this section, featureless, unchanging, ever smelly, pipe ending in yet another flow control flap. Dead end then?, we must be at the Thames. Cant hurt to look at the outfall then can it. I manovered my camera past the toilet paper and through a small gap and pinged off a flash. The pipe continued several meters into the darkness, this cant be the outfall. There was still more to see, we just needed to get past this chunk of metal.

3,2,1 Push. I squeezed round and jammed a maglite in the gap for safety. Slowly climbing to my feet my light was devoured by the cavernous space that lay before me, one phrase running through my mind, "fu** its huge". The tunnel stretched and skewed to over four times its average size as we entered into sections of the tunnel that were culverted before it became a sewer. Large sloped banks channeled the remaining sewage into the middle. After a brief investigation for possible exit points i returned for the others.

We continued downstream passing several reinforced sections and junctions with other sewers before the banks curved up out of the water, forming two walkways either side of a deep channel for the Tyburn to continue its journey. The tunnel kept increasing in size every hundred yards before the channel curved left and off down a side pipe and into the LLS No.1. This was the last time we would see any remains of the Tyburn, before us lay a seemingly dry array of chambers, rcp and its outfall with the Thames.